Heat oven to 400°F. Slice the top off the garlic, drizzle with olive oil, wrap in foil, and roast for 40 minutes until soft.

Peel and cut potatoes into 1-inch chunks. Cover with cold salted water, bring to a boil, then simmer until fork-tender, 15-18 minutes. Drain and return to pot to steam dry.

In a small saucepan, warm butter and milk over low heat until butter melts.

Rice potatoes back into the pot. Squeeze in roasted garlic cloves, then fold in warm milk mixture. Season with salt and pepper.

Transfer to a serving bowl, create a swoop, drizzle with extra melted butter, and top with chives.